This file also changes the Wildlife Friend skill or whatever it is. By default someone with this skill (I honestly don't know what it is, might be hidden?) gets the chance of startling dropped by 20. Since this mod drops the chance of startling a deer at mid-range distance to 25, I have dropped this to 5. Once the skill is maxed, it normally drops the chance by 100- meaning the sim can get right up to the animal no problem. This mod will drop that to 50. This is because the chance to startle a deer when you're very close is now 47, so there's no need for it to be that high. It also means that you won't get an enormous jump in your sims' ability to approach animals just by getting one skill point.
Not entirely sure how all that works, but the gist of it is that this will make it harder to startle deer, no matter what.